NJU7342 - 1 - single-phase dc brushless motor driver ic general description the NJU7342 is a single-phase dc brushless motor driver ic for small and high power fan-motor applications. it incorporates mos-fet tran sistors in output stage which can provide an ultra low saturation output voltage in high current operation. it also incorporates high slew rate amplifiers and feed-back resisters to prov ide optimized output wave for low noise motor driving. the NJU7342 is available in small and thin surface mount packages msop8 (vsp8) and msop8 (tvsp8) which provide downsizing and thinning in high power motor applications. package outline features ? operating voltage v dd =2.4 to 5.5v ? low operating current ? low saturation output voltage vsat= 0.35v @io= 250ma ? c-mos technology ? package outline msop8 (vsp8)* msop8 (tvsp8)** *meet jedec mo-187-da **meet jedec mo-187-da / thin type block diagram pin function 1: aout 2: amp-in 3: amp+in 4: gnd 5: nc 6: nc 7: bout 8: v dd 1 2 7 8 + + ? ? a b rf rf 3 4 5 6 gnd NJU7342r (msop8(vsp8)) NJU7342rb1 (msop8(tvsp8))
NJU7342 - 4 - abusolute maximum ratings (ta=25 c) parameter ratings symbol (unit) note supply voltage +7 v dd (v) input voltage -0.3 v dd +0.3 v id (v) operating temperature range -40 +85 topr ( c) storage temperature range -50 +150 tstg ( c) power dissipation 400 p d (mw) device itself recommended operating conditions v dd =2.4v to 5.5v electrical characteristics (ta=25c, v dd =5v) parameter sysmbol condition min. typ. max. unit input offset voltage v io - -5 - 5 mv input common mode voltage range v icm - 0.4 to 4.0 - - v v om+ io=+250ma 4.55 4.65 - v maximum output voltage range v om - io= -250ma - 0.35 0.45 v operating current i dd - - 3.0 4.0 ma feedback resistance r f - 22.0 27.5 33.0 k ? (note) the oscillation comes to happen easily in the state that there is no load of current and gain is low. in this case, please adjust the stray ca pacity of the output terminal to 100pf or less.
NJU7342 - 5 - application circuit s n s n v dd hall bias resistor hall sensor motor a mateur motor stater 1 2 3 4 5 6 7 8 + + ? ? a b rf rf
NJU7342 - 4 - application note the NJU7342 is a single- phase dc brushless motor driver ic in small msop8 (vsp8) / msop8 (tvsp8) packages. with minimal external components, that can drive up to 250ma of motor current for small fan application. [application circuit example] in+ in- vdd vss outb outa moto r hall element r1 r2 NJU7342 v+ gnd c1 d1 [design notes] above application example is designed for 5v operation. it uses the following components: hall elements: hw101a (ake) 1. selection of c1 and d1: c1 is used for a noise reduction purpose. a typical value is 0.1uf. optimize the value in actual operat ing conditions if necessary. d1 is a diode for protection against reverse voltage supply. silicon rectifier diode (w o3c, 10d1 and equivalent) is appropriate. 2. design of hall elem ent bias resistance ( r1 and r2 ) hall amplifier is a differential amplifier. the common-mode input voltage is between 0.4v and v dd-1v and the input signal must be within the range. non-excitation hall bias voltage is to be set at a half of vdd for effective use of common-mode input voltage range. therefore the same value of ha ll bias resistors is selected for r1 and r2. given that the bias current is set to be 5ma by hw101a datasheet, r1 and r2 can be determined as follows:
NJU7342 - 5 - the output voltage of hall elements is influenced by the bias current and magnetic flux density of hall elements. the optimum input voltage of nju 7342 is 100mvp-p and higher. with such input voltage, the highest efficiency can be obtained. the specifications on this data book are only given for information, without any guarantee as regards either mistakes or omissions. the application circuit in this data book are described only to show representative usages of the product and not intended for the guarantee or permission of any ri g ht includin g the industrial ri g hts. ? = = ? = = = + + ? 300 2 1 0 . 1 10 5 5 2 1 3 r r k ihbias vdd rin r r
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